Combined cycle pulse detonation turbine engine

ABSTRACT

A turbofan engine includes a pulse detonation system to create a temperature rise and a pressure rise within the engine to generate thrust from the engine. The system includes a pulse detonation augmentor including a shock tube sub-system. The shock tube sub-system includes a plurality of shock tubes which mix air and fuel introduced to the pulse detonation augmentor and detonate the mixture. The detonation creates hot combustion gases which are directed from the engine to produce thrust for the engine. Alternatively, the system includes a pulse detonation augmentation system that replaces a core engine of a turbo-fan engine.

BACKGROUND OF THE INVENTION

[0001] This invention relates to gas turbine engines, and moreparticularly, to a pulse detonation system for a turbofan engine.

[0002] Variable cycle turbofan ramjet engines may be used to provideaircraft flight speeds between low subsonic Mach numbers to highsupersonic Mach numbers of about Mach 6. Known engines, as described inU.S. Pat. No. 5,694,768, include a core engine system and a dual modeaugmentor. The dual mode augmentor provides additional heat to exhaustairflow exiting the core engine system to increase engine thrust. Thecore engine system provides power to drive a fan assembly and typicallyincludes in serial, axial flow relationship, a compressor, a combustor,a high pressure turbine, and a low pressure turbine. The dual modeaugmentor is positioned downstream from the core engine and receives airfrom the core engine and a bypass duct surrounding the core engine.

[0003] Known engines can operate over a wide range of flight speedoperations if several different combustion systems are utilized. Duringflight speed operations from take-off to approximately Mach 3, the coreengine and an engine fan system provide airflow at a pressure andquantity used by the augmentor to produce thrust for the engine. Tomaintain flight speed operations between Mach 3 and Mach 6, the coreengine system is shut-down and ram air flow is introduced into the dualmode augmentor either by windmilling the fan system or by utilizing anauxiliary ram duct. To sustain flight speed operations above Mach 6,either a separate supersonic combustion system, i.e., a scramjet, isused, or a separate rocket-based thrust producing system is used. Toachieve flight speed operations in space, the rocket-based thrustproducing system is used. As a result, for an engine to operateefficiently over a wide range of operating flight speeds, severaldifferent combustion systems are used.

BRIEF SUMMARY OF THE INVENTION

[0004] In an exemplary embodiment, a turbofan engine includes a pulsedetonation system to provide turbofan engine thrust to permit the engineto operate efficiently over a wide range of operating flight speeds. Thepulse detonation system includes a first pulse detonation augmentorwhich creates a temperature rise and a pressure rise within the turbofanengine to generate turbofan engine thrust. The pulse detonationaugmentor includes a shock tube sub-system including a plurality ofshock tubes. The shock tubes mix the air and fuel prior to detonatingthe mixture.

[0005] During operation, air and fuel are introduced to the pulsedetonation system. The pulse detonation augmentor mixes the air and fueland detonates the resulting mixture. The detonation produces hotcombustion gases which have increased temperature and pressure and aredirected from the engine to produce thrust.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006]FIG. 1 is a cross-sectional side view of a turbofan engineincluding a pulse detonation system;

[0007]FIG. 2 is a cross-sectional view of a pulse detonation augmentorused with the pulse detonation system shown in FIG. 1 taken along lines2-2;

[0008]FIG. 3 is a cross-sectional side view of an alternative embodimentof a turbofan engine in a low flight speed mode of operation;

[0009]FIG. 4 is a cross-sectional view of another embodiment of aturbofan engine including a pulse detonation core replacement augmentorassembly used to replace a core engine shown in FIG. 1;

[0010]FIG. 5 is a cross-sectional view of the turbofan engine shown inFIG. 4 in a ram duct mode of operation; and

[0011]FIG. 6 is a cross-sectional view of the turbofan engine shown inFIG. 4 in a rocket mode of operation.

DETAILED DESCRIPTION OF THE INVENTION

[0012]FIG. 1 is a cross-sectional side view of a turbofan engine 10including a pulse detonation system 12. FIG. 2 is a cross sectional viewof a pulse detonation augmentor 13 taken along lines 2-2 shown inFIG. 1. In one embodiment, turbofan engine 10 is an F110/129 engineavailable from General Electric Aircraft Engines, Cincinnati, Ohio.Engine 10 has a generally longitudinally extending axis or centerline 14extending in a forward direction 16 and an aft direction 18. Engine 10includes a core engine 30 which includes a high pressure compressor 34,a combustor 36, a high pressure turbine 38, and a power turbine or a lowpressure turbine 39 all arranged in a serial, axial flow relationship.In alternative embodiments, engine 10 includes a core fan assembly (notshown).

[0013] Pulse detonation system 12 is disposed downstream from both coreengine 30 and receives core engine combustion gases from core engine 30.Pulse detonation system 12 creates a temperature rise and a pressurerise within engine 10 without the use of turbomachinery included withincore engine 30 to generate thrust from engine 10. Pulse detonationsystem 12 includes pulse detonation augmentor 13 which includes an inletside 70, an outlet side 72, and a shock tube sub-system 74. Inlet side70 is upstream from outlet side 72 and circumferentially surrounds anengine centerbody 76.

[0014] Shock tube sub-system 74 includes a plurality of shock tubes 78extending between pulse detonation augmentor inlet side 70 and pulsedetonation augmentor outlet side 72. Shock tubes 78 permit fuel and airentering pulse detonation system 12 to mix and detonate. Each shock tube78 has a circular cross-sectional profile and shock tube sub-system 74has a circular cross-sectional profile. In one embodiment, shock tubesub-system has a non-circular cross-sectional profile. Shock tubes 78extend from core engine 30 to a converging-diverging exhaust nozzle 84.Exhaust nozzle 84 is disposed downstream from pulse detonation system 12and shock tubes 78.

[0015] During operation, airflow enters engine 10 and fuel is introducedto core engine 30. The air and fuel are mixed and ignited within coreengine 30 to generate hot combustion gases. Specifically, pressurizedair from high pressure compressor 34 is mixed with fuel in combustor 36and ignited, thereby generating combustion gases. Such combustion gasesdrive high pressure turbine 38 which drives high pressure compressor 34.The combustion gases are discharged from high pressure turbine 38 intolow pressure turbine 39. The core airflow is discharged from lowpressure turbine 39.

[0016] The combined airflow is channeled into pulse detonation system 12and mixed with additional fuel introduced to engine 10. Pulse detonationsystem 12 detonates the mixture to create a temperature rise and apressure rise within engine 10, thus generating thrust from engine 10.In one embodiment, system 12 is controlled with a very high speedvalving system capable of operating at between 500 and 1000 cycles persecond or higher and a spark or plasma ignition system. In anotherembodiment, system 12 is controlled with a continuous detonationvalveless system that incorporates a pre-burning device. In yet anotherembodiment, system 12 utilizes a variable geometry mixer/injector tocontrol off-design tailoring of outlet gases within shock tubesub-system 74. Alternatively, system 12 incorporates elements of theprevious three embodiments for control.

[0017]FIG. 3 is a cross-sectional side view of an alternative embodimentof a turbofan engine 100 including a pulse detonation system 102 in alow flight speed mode of operation. Engine 100 has a generallylongitudinally extending axis or centerline 104 extending in a forwarddirection 106 and an aft direction 108. Engine 100 includes a coreengine 110 which includes a high pressure compressor 114, a combustor116, a high pressure turbine 117, and a power turbine or a low pressureturbine 118 all arranged in a serial, axial flow relationship. In analternative embodiment, engine 100 also includes a core engine includinga core fan assembly.

[0018] An auxiliary ram duct and valving system 150 is disposed radiallyoutward from core engine 110 and extends from an inlet side 152 ofengine 100 to pulse detonation system 102. Auxiliary ram duct andvalving system 150 includes an auxiliary ram duct 154 and a ram airvalve 156. Ram duct 154 includes an inlet 157 for receiving air. Inlet157 is annular and is in flow communication with ram duct 154. Ram airvalve 156 is disposed within ram duct 154 and is selectable to control aflow of ram air through auxiliary ram duct and valving system 150.During low flight speed modes of operation, ram air valve 156 is closedto prevent ram air from flowing through ram duct 154 into engine 100.During moderate supersonic Mach number flight speed operations betweenMach 3 and Mach 5, ram air valve 156 is open to permit ram air to flowthrough ram duct 154 into engine 100. Ram air valve 156 is alsopositionable at intermediate positions to control an amount of airflowchanneled into ram duct 154.

[0019] Pulse detonation system 102 is disposed downstream from coreengine 110 and auxiliary ram duct and valving system 150. Duringoperation, pulse detonation system 102 receives airflow from ram duct154 and core engine combustion gases from core engine 110. Pulsedetonation system 102 creates a temperature rise and a pressure risewithin engine 100 without the use of turbomachinery to generate thrustfrom engine 100. Pulse detonation system 102 includes a pulse detonationaugmentor 168 which includes an inlet side 170, an outlet side 172, anda shock tube sub-system 174. Inlet side 170 is upstream from outlet side172 and circumferentially surrounds an engine centerbody 176. Shock tubesubsystem 174 includes a plurality of shock tubes (not shown) extendingbetween pulse detonation augmentor inlet side 170 and pulse detonationaugmentor outlet side 172. Fuel and air are mixed and detonated withinshock tube sub-system 174 which extends from core engine 110 to anexhaust nozzle 180.

[0020] During low flight speed operation, airflow enters engine 100 andfuel is introduced to core engine 110. Specifically, pressurized airfrom high pressure compressor 114 is mixed with fuel in combustor 116and ignited, thereby generating combustion gases. Such combustion gasesdrive high pressure turbine 117 which drives high pressure compressor116. The combustion gases are discharged from high pressure turbine 117into low pressure turbine 118. The core airflow is discharged from lowpressure turbine 118. The airflow is channeled into pulse detonationsystem 102 and mixed with additional fuel introduced to engine 100.Pulse detonation system 102 creates a temperature rise and a pressurerise within engine 100 to generate thrust from engine 100.

[0021] During moderate supersonic Mach number flight speed operationsbetween Mach 3 and Mach 5, ram air valve 156 is placed in an openposition to permit ram air to enter ram duct 154 and flow to pulsedetonation system 102. Fuel is introduced to pulse detonation system 102and is mixed with ram air exiting ram duct 154. The fuel/air mixture isignited to produce combustion gases and thrust for engine 100.

[0022]FIG. 4 is a cross-sectional view of another embodiment of aturbofan engine 200 including a pulse detonation system 202. Engine 200has a generally longitudinally extending axis or centerline 204extending in a forward direction 206 and an aft direction 208. Engine200 includes a fan assembly 212 which includes a forward fan 214disposed in an inlet duct 216 of engine 200. Fan 214 includes aplurality of blades 218 circumferentially spaced around enginecenterline 204. Inlet guide vanes 220 are disposed in inlet duct 216upstream from forward fan 214 and extend between an engine hub 222 andan engine casing 224. Engine 200 also includes a turbine sub-system 230disposed in flow communication with forward fan 214. Turbine sub-system230 includes a turbine 232 disposed in flow communication with forwardfan 214 and including a plurality of blades 234 extending radiallyoutward from engine centerline 204.

[0023] Pulse detonation system 202 creates a temperature rise and apressure rise within engine 200 without the use of turbomachinery togenerate thrust for engine 200. Pulse detonation system 202 includes apulse detonation augmentor 240 and a pulse detonation core replacementaugmentor assembly 242. Pulse detonation augmentor 240 includes an inletside 250, an outlet side 252, and a shock tube sub-system 254. Inletside 250 is upstream from outlet side 252 and circumferentiallysurrounds an engine centerbody 256. Shock tube sub-system 254 includes aplurality of shock tubes (not shown) extending between pulse detonationaugmentor inlet side 250 and pulse detonation augmentor outlet side 252.The shock tubes permit fuel and air entering pulse detonation system 202to mix and detonate to provide thrust from engine 200.

[0024] Pulse detonation core replacement augmentor assembly 242 includesan inlet side 260, an outlet side 262, and a shock tube sub-system 264.Inlet side 260 is upstream from outlet side 262 and circumferentiallysurrounds an engine centerbody 266. Inlet side 266 includes an annularinlet 268 which permits airflow to enter pulse detonation corereplacement augmentor assembly 242. Shock tube sub-system 264 includes aplurality of shock tubes (not shown) extending between pulse detonationcore replacement augmentor assembly inlet side 260 and pulse detonationcore replacement augmentor assembly outlet side 262 andcircumferentially disposed around engine centerline 204

[0025] The shock tubes permit fuel and air entering pulse detonationsystem 202 to mix and detonate. The shock tubes also direct the hotcombustion gases to pulse detonation augmentor 240. Pulse detonationcore replacement augmentor assembly 242 replaces a core engine, such ascore engine 110 (shown in FIG. 3) of engine 100 (shown in FIG. 3).

[0026] Turbine sub-system 230 is disposed between pulse detonationaugmentor 240 and pulse detonation core replacement augmentor assembly242. Accordingly, turbine sub-system turbine 232 is in flowcommunication with pulse detonation augmentor 240 and pulse detonationcore replacement augmentor assembly 242. A cooling air pump 270 isdisposed radially inward from pulse detonation core replacementaugmentor assembly 242 and provides cooling air to turbine sub-system230. Cooling air pump 270 is disposed on a shaft (not shown) whichconnects turbine 232 with forward fan 214.

[0027] Engine 200 also includes an ejector/mixer 272 disposed upstreamfrom turbine sub-system turbine 232. Ejector/mixer 272 controls themixture of hot high pressure gases exiting pulse detonation corereplacement augmentor assembly 242 and flowing to turbine 232.Ejector/mixer 272 also controls an amount of cooling air flowing throughpulse detonation core replacement augmentor assembly 242, thuspermitting turbine 232 to operate efficiently from engine start-upoperating conditions to engine full-power operating conditions. In oneembodiment, engine 200 also incorporates a shock tube flow adjustmentschedule (not shown) and an inlet flow/shock tube operating bandschedule (not shown) to enable turbine 232 to function through acomplete range of engine operating conditions.

[0028] An auxiliary ram duct and valving system 280 is disposed radiallyoutward from pulse detonation system 202 and extends from an inlet side282 of engine 200 to pulse detonation augmentor 240. Auxiliary ram ductand valving system 280 includes an auxiliary ram duct 284 and a ram airvalve 286. Ram duct 284 surrounds inlet guide vanes 220, and forward fan214, and includes an inlet 287 for receiving air upstream from inletguide vanes 220. Inlet 287 is annular and is in flow communication withram duct 284. Ram air valve 286 is disposed within ram duct 284 and isselectable to control a flow of ram air through auxiliary ram duct andvalving system 280. During low flight speed modes of operation, ram airvalve 286 is closed to prevent ram air from flowing through ram duct 284into engine 200. During moderate supersonic Mach number flight speedoperations between Mach 3 and Mach 5, ram air valve 286 is opened topermit ram air to flow through ram duct 284 into engine 200. Ram airvalve 286 is also positionable at intermediate positions to control anamount of airflow channeled into ram duct 284.

[0029] Engine 200 also includes an oxidizer injection system (not shownin FIG. 4). The oxidizer injection system is upstream from first pulsedetonation augmentor 240 and in flow communication with pulse detonationaugmentor 240 and permits an oxidizer (not shown) to be introduced intoengine 200 to enable engine 200 to operate in a rocket mode of operationfor flight altitudes at the edge of space and beyond. In one embodiment,the oxidizer is liquid oxygen. Alternatively, the oxidizer is liquidair.

[0030] During powered fan modes of operation or low flight speed modesof operation, ram air valve 286 is closed to prevent airflow fromentering ram duct 284 and instead airflow enters engine 200 and passesthrough forward fan 214. Airflow is discharged axially from forward fan214 into pulse detonation core replacement augmentor assembly inlet 268.As air enters pulse detonation core replacement augmentor assembly 242,fuel is introduced into pulse detonation core replacement augmentorassembly 242. The pulse detonation core replacement augmentor assemblyshock tubes combine the air and fuel and detonate the mixture, thusincreasing the temperature and pressure of the flow through pulsedetonation core replacement augmentor assembly 242.

[0031] During powered fan modes of operation, ejector/mixer 272 tailorsthe mixture of hot high pressure gases exiting pulse detonation corereplacement augmentor assembly 242 and flowing to turbine 232.Ejector/mixer 272 also tailors an amount of cooling air flowing throughpulse detonation core replacement augmentor assembly 242 to permitturbine 232 to operate within engine 200. Accordingly, during suchpowered fan modes of operation, a portion of the hot gases are directedthrough ejector/mixer 272 around turbine 232 to permit turbine 232 tooperate from engine start-up operating conditions through enginefull-power operating conditions. During such modes of operation, turbine232 drives forward fan 214.

[0032] The hot gases are discharged from pulse detonation corereplacement augmentor assembly 242 into pulse detonation augmentor 240.Additional fuel is introduced into pulse detonation augmentor 240 whichmixes the hot gas mixture and the fuel and detonates the mixture.Detonating the mixture creates an additional temperature and pressurerise, resulting in thrust from engine 200. The powered fan mode ofoperation permits engine 200 to produce thrust for flight speedoperations to about Mach 3.

[0033]FIG. 5 is a cross-sectional view of turbofan engine 200 in a ramduct mode of operation. The ram duct mode of operation permits engine200 to operate with flight speeds between approximately Mach 3 and Mach6. During the ram duct mode of operation, inlet guide vanes 220 arerotated to a closed position to substantially prevent airflow fromentering forward fan 214 and to substantially cocoon forward fan 214 andturbine sub-system 230. Ram air valve 286 is rotated opened to permitram air to enter ram duct 284 and flow to pulse detonation system 202.Fuel is introduced to pulse detonation system 202 within pulsedetonation augmentor 240 and is mixed with ram air exiting ram duct 284.The fuel/air mixture is ignited to produce combustion gases and thrustfor engine 200. An auxiliary heat exchanger (not shown) provides coolair to cool cocooned forward fan 214 and turbine sub-system 230.

[0034]FIG. 6 is a cross-sectional view of turbofan engine 200 shown in arocket mode of operation and including an oxidizer injection sub-system290. The rocket mode of operation permits engine 200 to operate withflight altitudes at the edge of space and flight speeds greater thanMach 6. During the rocket mode of operation, inlet guide vanes 220remain rotated in a closed position to substantially prevent airflowfrom entering forward fan 214 and turbine sub-system 230. Ram air valve286 is rotated closed to prevent ram air from entering ram duct 284 andpulse detonation system 202. Oxidizer injection system 290 introduces anoxidizer (not shown) to pulse detonation system 202 and directs theoxidizer downstream towards pulse detonation augmentor 240. Theoxidizer, combined with injected fuel, produces thrust from engine 200and helps to cool engine 200 during operation.

[0035] The above-described pulse detonation system includes at least onepulse detonation augmentor which produces engine thrust without the useof turbomachinery. As a result, engines using the pulse detonationsystem obtain increased thrust over baseline engines operating withoutthe pulse detonation system. As a result, a pulse detonation system isprovided which permits an engine to operate with a high efficiency andperformance over a wide range of operating flight speeds.

[0036] While the invention has been described in terms of variousspecific embodiments, those skilled in the art will recognize that theinvention can be practiced with modification within the spirit and scopeof the claims.

What is claimed is:
 1. A method for generating turbofan engine thrustwith a pulse detonation system, the pulse detonation system creates atemperature rise and a pressure rise within the turbofan engine withoutthe use of turbomachinery, the pulse detonation system including a firstpulse detonation augmentor including an inlet side, an outlet side, anda shock tube sub-system extending therebetween, the shock tubesub-system including a plurality of shock tubes, said method comprisingthe steps of: introducing fuel and air to the turbofan engine; mixingfuel and air in the first pulse detonation augmentor shock tubes; anddetonating the fuel and air mixture within the first pulse detonationaugmentor shock tubes to increase the temperature and pressure withinthe turbofan engine and to generate turbofan engine thrust.
 2. A methodin accordance with claim 1 wherein the turbofan engine further includesan auxiliary ram duct and valving system, the first pulse detonationaugmentor in flow communication with the auxiliary ram duct and valvingsystem, said step of introducing fuel and air further comprises the stepof introducing fuel and air to the pulse detonation augmentor throughthe auxiliary ram duct and valving system.
 3. A method in accordancewith claim 1 wherein the engine further includes a pulse detonation corereplacement augmentor assembly including a plurality of shock tubes, thefirst pulse detonation augmentor downstream from the pulse detonationcore replacement augmentor assembly, the first pulse detonationaugmentor replacing a core engine of the turbofan engine, said methodfurther comprising the steps of: introducing air and fuel into the pulsedetonation core replacement augmentor assembly shock tubes, mixing fueland air in the pulse detonation core replacement augmentor assembly; anddelivering the fuel and air mixture to the first pulse detonationaugmentor.
 4. A method in accordance with claim 3 wherein the enginefurther includes a turbine sub-system, a cooling air pump, anejector/mixer, and an oxidizer injection system, the turbine sub-systemdisposed between the first pulse detonation augmentor and the pulsedetonation core replacement augmentor assembly, the cooling air pumpdisposed radially inward from the pulse detonation core replacementaugmentor assembly, the ejector/mixer positioned radially outward fromthe pulse detonation core replacement augmentor assembly, said methodfurther comprising the steps of: cooling the turbofan engine with thecooling air pump disposed radially inward from the pulse detonation corereplacement augmentor assembly; and controlling the amount of highpressure gas exiting the pulse detonation core replacement augmentorassembly with the ejector/mixer.
 5. A method in accordance with claim 4further comprising the step of introducing an oxidizer into the firstpulse detonation augmentor with the oxidizer injection system.
 6. Apulse detonation system for a turbofan engine, said pulse detonationsystem configured to create a temperature rise and a pressure risewithin the turbofan engine and to increase turbofan engine thrust, saidpulse detonation system comprising a first pulse detonation augmentorcomprising an inlet side, an outlet side, and a shock tube sub-systemdisposed therebetween, said shock tube subsystem comprising a pluralityof shock tubes extending from said pulse detonation augmentor inlet sideto said pulse detonation augmentor outlet side, said shock tubesconfigured to detonate a fuel mixture.
 7. A pulse detonation system inaccordance with claim 6 wherein said first pulse detonation augmentor isdownstream from a core engine powering the turbofan engine.
 8. A pulsedetonation system in accordance with claim 7 wherein the turbofan enginefurther comprises an auxiliary ram duct and valving system, said firstpulse detonation augmentor in flow communication with the auxiliary ramduct and valving system.
 9. A pulse detonation system in accordance withclaim 6 further comprising a pulse detonation core replacement augmentorassembly comprising a plurality of shock tubes configured to detonatethe fuel mixture, said first pulse detonation augmentor downstream fromsaid pulse detonation core replacement augmentor assembly in flowcommunication with said pulse detonation core replacement augmentorassembly, said first pulse detonation augmentor replacing a core engineof the turbofan engine.
 10. A pulse detonation system in accordance withclaim 9 further comprising a turbine sub-system disposed between saidfirst detonation augmentor and said pulse detonation core replacementaugmentor assembly.
 11. A pulse detonation system in accordance withclaim 10 further comprising a cooling air pump configured to supplycooling air to said turbine subsystem, said cooling air pump disposedradially inward from said pulse detonation core replacement augmentorassembly.
 12. A pulse detonation system in accordance with claim 11further comprising an ejector/mixer upstream from said turbinesub-system, said ejector/mixer configured to control an amount of highpressure gas exiting said pulse detonation core replacement augmentorassembly.
 13. A pulse detonation system in accordance with claim 12further comprising an oxidizer injection system positioned in flowcommunication with said first detonation augmentor.
 14. A turbofanengine comprising: an inlet portion; an exhaust portion positionedco-axially with said inlet portion; and a pulse detonation systempositioned between said turbofan inlet portion and said turbofan exhaustportion, said pulse detonation system configured to create a temperaturerise and a pressure rise within said turbofan engine and to increaseturbofan engine thrust, said pulse detonation system comprising a firstpulse detonation augmentor comprising an inlet side, an outlet side, anda shock tube subsystem extending therebetween, said shock tubesub-system comprising a plurality of shock tubes configured to detonatea fuel mixture.
 15. A turbofan engine in accordance with claim 14further comprising a core engine configured to power said turbofanengine, an auxiliary ram duct and valving system, said first pulsedetonation augmentor downstream from said core engine in flowcommunication with said auxiliary ram duct and valving system.
 16. Aturbofan engine in accordance with claim 14 further comprising a pulsedetonation core replacement augmentor assembly in flow communicationwith said first pulse detonation augmentor, said pulse detonation corereplacement augmentor assembly comprising an inlet side, an exhaustside, and a plurality of shock tubes extending therebetween, said shocktubes configured to detonate the fuel mixture.
 17. A turbofan engine inaccordance with claim 16 further comprising a turbine sub-system, saidturbine sub-system positioned between said first pulse detonationaugmentor and said pulse detonation core replacement augmentor assembly,said pulse detonation core replacement augmentor assembly in flowcommunication with said turbine sub-system.
 18. A turbofan engine inaccordance with claim 17 further comprising a cooling air pumpconfigured to supply cooling air to said turbine sub-system, saidcooling air pump disposed radially inward from said pulse detonationcore replacement augmentor assembly.
 19. A turbofan engine in accordancewith claim 18 further comprising an ejector/mixer configured to controlan amount of high pressure gas exiting said pulse detonation corereplacement augmentor assembly, said ejector/mixer upstream from saidfirst detonation augmentor.
 20. A turbofan engine in accordance withclaim 19 further comprising an oxidizer injection system positioned inflow communication with said first detonation augmentor.